Pure fluid control element

ABSTRACT

In order to perform both digital and analog functions when relatively small loads are encountered by fluid leaving its vent passages, a pure fluid control element comprises main fluid inlet means supplied with a fluid to be controlled, fluid flow outlet means disposed downstream of the main fluid inlet means at a predetermined distance to receive the controlled flow from the main inlet means, vortex means between the main fluid inlet means and fluid flow outlet means for producing a vortex flow to attract the fluid from the main inlet means, vent passage means adjacent the fluid flow outlet means and extending into said vortex means, and control fluid inlet means extending into said vortex means in the same direction as the vortex flow and supplied with a control flow for regulating the vortex flow to control the deflection of the fluid from the main fluid inlet means.

United States Patent [1 1 Kawabata 1 Sept. 25, 1973 [73] Assignee:Toyoda Koki Kabushiki Kaisha,

Kariya City, Japan [22] Filed: Nov. 15, 1971 [21] Appl. No.: 198,737

Related US. Application Data Minoru Kawabata, Kariya, Japan [63]Continuation of Ser. No, 3,023, Jan. 15, 1970,

Laakanemi et al. 137/815 Mayer 137/815 Primary ExaminerSamuel ScottAtt0rne \'Brisebois & Kruger 57 ABSTRACT In order to perform bothdigital and analog functions when relatively small loads are encounteredby fluid leaving its vent passages,.a pure fluid control elementcomprises main fluid inlet means supplied with a fluid to be controlled,fluid flow outlet means disposed downstream of the main fluid inletmeans at a predetermined distance to receive the controlled flow fromthe main inlet means, vortex means between the main fluid inlet meansand fluid flow outlet means for producing a vortex flow to attract thefluid from the main inlet means, vent passage means adjacent the fluidflow outlet means and extending into said vortex means, and controlfluid inlet means extending into said vortex means in the same directionas the vortex flow and supplied with a control flow for regulating thevortex flow to control the deflection of the fluid from the main fluidinlet means.

4 Claims, 3 Drawing Figures PATENTEDSEPZSIQB 3.760.828

sum 1 ur 2 FIG. 1

1 PURE FLUID CONTROL ELEMENT This is a continuation of application Ser.No. 003,023, filed Jan. 15, 1970, now abandoned.

SUMMARY OF THE INVENTION This invention relates to pure fluid controlelements, and more particularly to a pure fluid control element whichcan perform both digital and analog functions.

Conventionally a fluid control system has been used wherein pure fluidcontrol elements having a digital characteristic and elements having ananalog characteristic are interconnected. However, no known elementsperform both digital and analog functions.

It is therefore an object of the invention to provide a novel and usefulpure fluid control element.

It is another object of this invention to provide a pure fluid controlelement performing both digital and analog functions whenrelatively.small or no loads are encountered by fluid leaving its ventpassages.

It is yet another object of the invention to provide a pure fluidcontrol element performing only an analog function when relatively largeloads are encountered by fluid leaving its vent passages.

It is a further object of the invention to provide a pure fluid controlelement wherein a small control pressure may deflect a large amount ofthe main fluid flow.

BRIEF DESCRIPTION OF THE DRAWINGS DESCRIPTION O THE INVENTION Referringnow to FIGS. 1 and 2, FIG. 1 is a bottom plan view of the upper part 1of a pure fluid control element according to the present invention whichis sealed to a flat plate 2. It should be apparent that the particularmeans by which the plates 1, 2 are secured together is not critical, solong as the connection is sufficiently tight to insure that no fluid canleak from the pure fluid element. Plates 1 and 2 may be made of a metal,plastic, ceramic, or any other suitable material, and for purposes ofillustration, these plates are shown as made of a transparent plastic.In this embodiment, the pure fluid control element comprises two flatplates, although it may be also made from three flat plates.

A main supply nozzle 10, the outlet of which is narrowed, is connectedto a supply passage 11. A pair of receiving ports 20 and 21, separatedby a divider 26, are positioned at a predetermined distance from themain supply nozzle 10 to receive fluid supplied through the main nozzle10. The receiving ports 20 and 21 are connected to output ports 24 and25 respectively. The fluid streams pass through the passages 22 and 23which gradually increase in cross-sectional area.

A pair of substantially circular and overlapping vortex chambers 30 and3-1 are formed between the main nozzle 10 and the receiving ports 20,21. These chambers 30, 31 are symmetrical with respect to the centerline 0 which passes through the main nozzle 10. Circular walls 32 and 33of the vortex chambers 30 and 31 terminate at the outlets of the mainnozzle 10 and at the receiving ports 20 and 21. A pair of controlnozzles 40 and 41, which are adjacent to the main nozzle 10 and oppositeto each other,extend tangentially into the vortex chambers 30 and 31with relatively small' partcircular walls 32a and 33a between the mainnozzle 10 and the control nozzles 40 and 41. The control nozzles 40 and41 are connected to control pipes 46 and 47 respectively. A fluid issupplied through control ports 44 and 45, and control passages 42 and 43as the controlling input. A pair of vent passages 50 and 51 arepositioned adjacent the receiving ports 20 and 21 respectively. The ventpassages 50 and 51 are opposite the receiving ports 20 and 21 and extendtangentially into the vortex chambers 30 and 31, terminating inrelatively small and part-circular walls 32b and 33b. Between thereceiving ports 20, 21 and vent passages 50, S1 reasonable spaces areprovided. The effective cross-sectional areas of the vent passages 50and 51 increase gradually from their inner ends toward their outer ends.The ends of the passages 50 and 51 are vented to the atmosphere. Fluidunder pressure, such as compressed air from a supply source (not shown),is supplied to the main nozzle 10 through a supply pipe 12 and thesupply passage 11. Pressure fluid passing through the receiving ports 20and 21 is fed to any other device which is to be operated by the fluidthrough the output passages 22, 23, the output ports 24, 25 and theoutput pipes 27, 28.

When the main pressure fluid, such as compressed air, is introduced intothe vortex chambers from the supply source, through the supply pipe 12,the supply port 11 and the main nozzle 10, the main fluid may bedeflected toward one of the vortex chambers, say the right vortexchamber 31 if some slight perturbation occurs in the main flow. Then thegreater part of the main fluid follows along the walls 33b and 33, toproduce a vortex flow within the right vortex-chamber 31. The mainstream of fluid is attracted by the vortex flow and is further-deflectedto the right and maintained stable,

In this stable condition, the greater part of the main fluid isdischarged to the atmosphere through the vent passage 51. Therefore, thereceiving port 21 receives the vortex chamber 31 through the controlport 45 and I the control nozzle 41, the pressure in the lower portionof the vortex chamber is raised to shift the center of the vortex flowupward, and thereby decrease the deflection of the main fluid to theright. In this case, the fluid flow into the receiving port 21 isincreased and the output pressure in the output port 25 is increased inpro portion to the control input. Therefore, the vent passage 51necessarily receives a decreased amount of the mainfluid.

Since the control nozzle 41 extends tangentially into the vortex chamber31 and the control How is introduced in the same direction as the vortexflow, a small control flow in the control nozzle 41 can divert a muchlarger main fluid flow from right to left. Thus, a large gain in outputpressure may be obtained by causing only a small increase in controlpressure.

When the control input supplied to the control nozzle 41 reaches apredetermined value, the main fluid is switched from right to left andis attracted to the left for stabilization by the vortex flow producedin the left vortex chamber 30. Since the greater part of the main streamof fluid has been deflected to the right, this stream produces vortexflow in the left vortex chamber 30 and is vented to the atmospherethrough the passage 50. Thus relatively low pressure is applied to theoutput port 24 through the outlet port 20. On the other hand, thepressure at the output port 25 tends to be negative. When a controlinput is introduced tangentially into the vortex chamber 30 through thecontrol nozzle 40, the pressure in the lower portion of the vortexchamber 30 is raised to shift the center of the vortex flow upward,thereby decreasing the leftward deflection of the main fluid. When thecontrol input reaches a predetermined value, the main fluid is shiftedfrom left to right.

Referring to FIG. 3, which shows the operating characteristic of theoutput pressure P in each of the output ports 24 and 25 as a function ofthe change in the control pressure PC in the control nozzle 41 with apredetermined biasing pressure applied to the control nozzle 40 and withthe main fluid initially deflected to the right vortex chamber 31, asolid line R shows the output pressure in the right output port 25 and asolid line L shows the output pressure in the left output port 24. Whenthe control pressure PC in the control nozzle 41 is zero, the outputpressure in the output port 25 is P01, and that in the output port 24 isP02. When the control pressure PC is increased, the output pressure inthe output port 25 is gradually increased, but that in the output port24 remains substantially constant. When the control pressure reachesPC2, the main fluid is shifted from right to left, so that the pressurein the output port 25 is suddenly decreased from P03 to P04, and that inthe output port 24 is suddenly increased from P to P06. When the controlpressure PC is further increased, the pressure in the output port 24 isgradually decreased,'but that in the output port 25 remainssubstantially constant. When the control pressure PC is furtherdecreased, the pressure in the output port 24 is gradually increasedwhile that in the output port 25 remains substantially constant.However, the main fluid is not shifted at the control pressure, PC2, butis shifted at a lower control pressure, PCl.

As will be understood from the above description, the pure fluid controlelement according to the present invention has a digital characteristicand also has an analog function except for switching conditions. Thus,the present element may be used as a digital component. Furthermore,this element may be used as an analog component, using only the analogcharacteristic, or both digital and analog characteristics may be used.Thus, the present invention has the advantage that one element may beutilized for a plurality of purposes.

The pressures in the vent passages 50 and 51 have characteristicssubstantially inverse to those in the output ports 24 and 25,respectively, and thus, devices responsive to relatively low loads maybe connected to the vent passages 50 and 51.

In the above embodiment, the vent passages 50 and 51 are vented to theatmosphere. However, when relatively high loads are applied to the ventpassages 50 and 51, experiments have shown that the element does nothave a digital characteristic, but has only an analog characteristic.

While only one specific embodiment of the invention has been described,it should be understood that the novel concept of the invention may beincorporated into other embodiments without departing from the basicprinciples of the invention as defined in the following claims.

What is claimed is:

l. A pure fluid control element comprising:

a main fluid inlet for receiving a fluid to be controlled,

a pair of fluid flow outlets positioned at a predetermined distancedownstream of said main fluid inlet to receive the fluid from said mainfluid inlet,

a pair of substantially circular and overlapping vortex chambers betweensaid main fluid inlet and fluid flow outlets and symmetricallypositioned with respect to the center line passing through said mainfluid inlet to produce a vortex flow which attracts the fluid from saidmain fluid inlet,

a pair of vent passages adjacent said fluid flow outlets and opposite toeach other and extending into said vortex chambers, respectively, and

a control inlet for each vortex chamber for aperiodically supplying toits respective vortex chamber a control fluid which acts on the vortexflow therein in order to control the deflection, of the fluid from themain fluid inlet, each control inlet being defined in part by a curvedwall extending into its respective vortex chamber to direct the fluidflow from that control inlet substantially tangentially of saidrespective chamber in the same direction as the vortex flow produced insaid respective chamber, whereby a gradual increase in the control fluidpressure supplied through the control inlet for one vortex chamber firstgradually transfers the pressure of fluid received through said mainfluid inlet from the vent in said one vortex chamber to the outlet inthe same chamber, and then abruptly transfers said pressure to the othervortex chamber when a threshold control fluid pressure is reached.

2. A pure fluid control element as claimed in claim 1, wherein one ofsaid pair of vent passages extends tangentially into each of said pairof vortex chambers.

3. A pure fluid control element as claimed in claim 1, wherein saidcontrol inlets are adjacent to the main fluid inlet and opposite to eachother.

4. A pure fluid control element as claimed in claim 1, wherein said pairof vortex chambers are each substantially circular and overlap, one ofsaid pair of vent passages extends tangentially into each of said vortexchambers, and one of said control inlets extends into each of said pairof vortex chambers, said control inlets being adjacent the main fluidinlet and opposite each other.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 a 7'DatecI 5 September 973 Inventor(s) MINORU KAWABATA It is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

[30] Foreign Application Priority Data January 31, 1969 Japan. f AI-7676 signed arid sealed this 9th day of April 19m.

(SEAL) Attest:

EDWARD MQFLETCHERJR. C. MARSHALL DANN Attesting Officer Commissioner ofPatents USCOMM-DC 60376-P69 w uss, eovzmmsm- PRINTING OFFICE: I90o-ass-au.

F ORM PO-l 050 (10-69)

1. A pure fluid control element comprising: a main fluid inlet forreceiving a fluid to be controlled, a pair of fluid flow outletspositioned at a predetermined distance downstream of said main fluidinlet to receive the fluid from said main fluid inlet, a pair ofsubstantially circular and overlapping vortex chambers between said mainfluid inlet and fluid flow outlets and symmetrically positioned withrespect to the center line passing through said main fluid inlet toproduce a vortex flow which attracts the fluid from said main fluidinlet, a pair of vent passages adjacent said fluid flow outlets andopposite to each other and extending into said vortex chambers,respectively, and a control inlet for each vortex chamber foraperiodically supplying to its respective vortex chamber a control fluidwhich acts on the vortex flow therein in order to control the deflectionof the fluid from the main fluid inlet, each control inlet being definedin part by a curved wall extending into its respective vortex chamber todirect the fluid flow from that control inlet substantially tangentiallyof said respective chamber in the same direction as the vortex flowproduced in said respective chamber, whereby a gradual increase in thecontrol fluid pressure supplied through the control inlet for one vortexchamber first gradually transfers the pressure of fluid received throughsaid main fluid inlet from the vent in said one vortex chamber to theoutlet in the same chamber, and then abruptly transfers said pressure tothe other vortex chamber when a threshold control fluid pressure isreached.
 2. A pure fluid control element as claimed in claim 1, whereinone of said pair of vent passages extends tangentially into each of saidpair of vortex chambers.
 3. A pure fluid control element as claimed inclaim 1, wherein said control inlets are adjacent to the main fluidinlet and opposite to each other.
 4. A pure fluid control element asclaimed in claim 1, wherein said pair of vortex chambers are eachsubstantially circular and overlap, one of said pair of vent passagesextends tangentially into each of said vortex chambers, and one of saidcontrol inlets extends into each of said pair of vortex chambers, saidcontrol inlets being adjacent the main fluid inlet and opposite eachother.